Goals: The ambitious twin-spacecraft Vega project aimed to deliver advanced lander modules on Venus, study the planet's atmosphere with balloons and then fly on for a close encounter with comet Halley.

Accomplishments: Both Vega 1 and its twin Vega 2 were tremendously successful. The Vega balloons drifted a third of the way around the planet, revealing cloud decks distinctly different from those seen by Pioneer Venus -- suggesting a change in Venus' atmosphere. Vega 1's lander lander set down in the Mermaid Plain north of Aphrodite and transmitted for 56 minutes. Its soil sampler deployed prematurely, spoiling the experiment, but the mass spectrometer returned important data. The Vega 1 bus flew on to study Halley as part of an international fleet sent to meet the comet made its journey through the inner solar system.